Case Study Additional Information

Figure 5-30 shows the existing WAN links and the planned campus infrastructure.

Figure 5-30 Case Study ACMC Hospital WAN Links and Planned Campus Infrastructure

Distribution

Remote Clinics

Figure 5-30 Case Study ACMC Hospital WAN Links and Planned Campus Infrastructure

Distribution

Remote Clinics

Smaller Buildings

Main Building 2

Children's Place

Smaller Buildings

Smaller Buildings

Main Building 2

Children's Place

Business Factors

The ACMC Hospital CIO realizes that WAN performance to the remote clinics is poor and that some new applications will require more bandwidth. These applications include programs that allow doctors at the central site to access medical images, such as digital X-rays, stored locally at the clinics. The CIO wants all the remote sites to have the same type of access.

The CIO wants to implement a long-term, cost-effective solution that allows high-bandwidth application deployment on the network and that allows for growth for the next two to five years. The CIO also wants to simplify planning, pricing, and deployment of future applications.

Technical Factors

There is no data about the bandwidth requirements of the new applications. Lab testing would provide better data, but ACMC does not have the time or money for testing. The CIO knows that because TCP adjusts to use the available bandwidth, such that when congestion occurs, there is no way to know how much bandwidth the present applications could ideally use unless extensive lab testing is done.

You discover that your site contact initially supplied you with an out-of-date network diagram. The hospital upgraded the 56 kbps links to 128 kbps a year ago and upgraded the WAN bandwidth at the largest clinic to 256 kbps last month. Therefore, the following is the current state of the WAN links:

■ The connection to the largest remote clinic now runs at 256 kbps.

■ The connections to two other remote clinics were upgraded from 56 kbps to 128 kbps.

■ The two remaining remote clinics have 56-kbps dialup connectivity.

The increased WAN bandwidth you recommend should last for two to five years.

For situations in which you cannot really determine how much WAN bandwidth is needed, one way to proceed is to multiply current traffic levels by a value of 1.5 or 2 per year. However, if the customer does not want to be concerned with needing even more bandwidth in the near future, multiply by bigger numbers. If you expect unknown applications to be added to the network, multiply by even bigger numbers. In this case study, assume that all clinics are to be upgraded to at least T1 access speed. (Pricing structures in many areas might even favor a full T1 over fractional T1 links.)

Was this article helpful?

0 0

Post a comment